Biodegradation of natural and synthetic estrogens in moving bed bioreactor

Estrogen hormones as a group of endocrine disruptive compounds(EDC) can interfere with endocrine system in humans and animals. The goal of this study was to investigate the elimination rate of Estrone(El), 17β-estradiol(E2) and 17α-ethinyl estradiol(EE2) in Moving Bed Bioreactor(MBBR). These analytes extracted by Dispersive Liquid-Liquid Microextraction(DLLME) technique, followed by derivatization, and detected by GC/MS. Estrogen removal efficiency in MBBR improved at high solid retention times(SRTs), which notion is owing to development of nitrification. Estrogen specific removal rate was between 0.22-1.45 μg·(g VSS)~(-1)·d~(-1) for natural and synthetic hormones. The adsorption rate was 0.9%-3.2%, 0-1.3%, and 0.7%-5.7% for El, E2, and EE2, respectively. In addition, the biodegradation rates were more than 95% for these compounds. These results illustrated that in MBBR,the biodegradation and the adsorption to biomass are considered as two significant routes for elimination of estrogenic compounds. As a whole, the deterioration rate of estrogens enhanced by MBBR compared to other biological wastewater treatment processes such as conventional activated sludge.     

Synthesis,characterization and immobilization of iron (III) pyridoxinato complex within Al-MCM-41 as catalyst for cycloalkanes oxidation

Biomimetic [Fe(pyridoxinato)₂OH·(H₂O)₃] non-hem complex designated as [Fe(L)₂OH·(H₂O)₃] was synthesized with basic solution of pyridoxine (Vitamin B₆) and FeCl₃ in methanol under reflux condition. It was then immobilized within the Al-MCM-41. Characterizations were carried out by powder X-ray diffraction, nitrogen adsorption desorption, FTIR and UV–Vis spectroscopy. It was found that pore volume, surface area, and pore diameter of Al-MCM-41 decreases after immobilization of iron complex. Density functional theory studies confirmed the experimental results of [Fe(L)₂OH·(H₂O)₃] complex. Fe-complex/Al-MCM-41 was found to successfully catalyze the oxidation of cyclohexane, cyclooctane and adamantane using H₂O₂ as oxidant with 45–90 % conversion toward the corresponding alcohols and ketones is considerable.     

Potential Development of Value-Added Fishery Products in Underutilized and Commercial Fish Species: Comparative Study of Lipid Quality Indicators

In this study, proximate and fatty acid composition in the edible flesh of eight underutilized and five commercial freshwater fish species were compared in order to evaluate the potential of these fish for development of functional value-added fishery products. The lipid content (% dry weight basis) of investigated fish species ranged from 3.44 to 9.25 in underutilized and 3.73–7.68 in commercial species. In comparison with underutilized fish species, commercial species had higher levels of protein (P < 0.05). The high proportion of EPA+DHA was found with Goldfish (524 mg/100 g flesh), Wels (422 mg/100 g flesh), and Crucian carp (354 mg/100 g flesh), all of which belonged to underutilized group. All studied fish (save Lenkoran) showed values higher than the minimum recommended DHA/EPA value (0.45). The ratios of n-6/n-3 found in this study were much lower (save Goatfish) than those cited as a harmful value (4.0 as the maximum value). The PUFA/SFA value of the present fish samples was higher at 1.57 for Goatfish, 1.02 for Lenkoran, 0.68 for Wels, all of these fish belonging to the underutilized group. The highest atherogenic and thrombogenicity index values were generally obtained for commercial species. It seems in respect of comparability of these lipid quality indicators, the underutilized fish species could be highly recommended as an important source of polyunsaturated fatty acids and Max-EPA products for humans consumption.     

Effects of temperature and impurities on the DC conductivity of snow

Several major parameters affecting the electrical behavior of natural snow, namely volume conductivity and density, liquid water content and conductivity of water melted from snow, are crucial for the characterization of the electrical performance of snow-covered HV insulators. However, little study has been devoted to this subject, despite of its importance. These parameters are found to vary significantly with snow composition and purity as well as with other parameters, such as temperature, airborne pollutants, electric field strength and polarity. From laboratory experiments carried out on a large number of snow samples, it was found that DC conductivity of snow shows a peak at about -2degC. This apparently curious behavior near the melting temperature is attributed to important changes to the microstructure of snow. A correlation between DC conductivity and snow temperature was established     

Modeling of the AC Arc Discharge on Snow-covered Insulators

A mathematical model for predicting the ac flashover voltage of snow-covered insulators is presented. The arc constant parameters in air gaps and inside snow, as well as the arc reignition condition are determined using a cylindrical model. The effects of the arc length on the arc constants parameters are also investigated. The model is then applied to an EPDM insulator artificially covered with natural snow. There is good concordance between the flashover results determined from the mathematical model and those obtained experimentally.     

Determination of 4-nonylphenol and 4-tert-octylphenol compounds in various types of wastewater and their removal rates in different treatment processes in nine wastewater treatment plants of Iran

Alkylphenols(APs), considered as xenoestrogenic compounds, mainly exist as 4-nonylphenol(4-NP) and 4-tertoctylphenol(4-t-OP) in environments. The high stability and accumulation of APs in aquatic systems have caused endocrine disruption. In this study we measured APs in the wastewater influent and effluent samples, from the urban, rural, livestock, commercial and hospital wastewater treatment plants(WWTPs) in Iran. Dispersive liquid–liquid microextraction(DLLME) combined with gas chromatography–mass spectrometry(GC–MS) was used for the extraction and determination of 4-NP and 4-t-OP. In these treatment plants, various processes such as activated sludge, aerated lagoon, moving bed biofilm reactor and activated sludge along with wetland were applied. The highest concentration of 4-NP and 4-t-OP was observed in commercial and livestock sewages. The activated sludge along with wetland and then the MBBR process showed the highest removal rates of pollutants. The rates of biodegradability and accumulation in sludge were determined and also the specific adsorption coefficient Kdand the organic carbon–water partition coefficient kOCof the sludge for APs were calculated.     

Multi-objective discrete urban road network design

This paper addresses the problem of designing urban road networks in a multi-objective decision making framework. Given a base network with only two-way links, and the candidate lane addition and link construction projects, the problem is to find the optimal combination of one-way and two-way links, the optimal selection of network capacity expansion projects, and the optimal lane allocations on two-way links to optimize the reserve capacity of the network, and two new travel time related performance measures. The problem is considered in two variations; in the first scenario, two-way links may have different numbers of lanes in each direction and in the second scenario, two-way links must have equal number of lanes in each direction. The proposed variations are formulated as mixed-integer programming problems with equilibrium constraints. A hybrid genetic algorithm, an evolutionary simulated annealing, and a hybrid artificial bee colony algorithm are proposed to solve these two new problems. A new measure is also proposed to evaluate the effectiveness of the three algorithms. Computational results for both problems are presented.     

An enhanced beam search algorithm for the Shortest Common Supersequence Problem

The Shortest Common Supersequence Problem asks to obtain a shortest string that is a supersequence of every member of a given set of strings. It has applications, among others, in data compression and oligonucleotide microarray production. The problem is NP-hard, and the existing exact solutions are impractical for large instances. In this paper, a new beam search algorithm is proposed for the problem, which employs a probabilistic heuristic and uses the dominance property to further prune the search space. The proposed algorithm is compared with three recent algorithms proposed for the problem on both random and biological sequences, outperforming them all by quickly providing solutions of higher average quality in all the experimental cases. The Java source and binary files of the proposed IBS_SCS algorithm and our implementation of the DR algorithm and all the random and real datasets used in this paper are freely available upon request.     

CQARPL: Congestion and QoS-aware RPL for IoT applications under heavy traffic

The Journal of Supercomputing - The Internet of Things (IoT) provides a common platform to connect the heterogeneous devices over the internet. Hence, the number of devices connected via the...